.aler {
    position: absolute;
    z-index: 9999;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: #fff;
    animation: change;
}

@keyframes change {
    0% {
        left: 100%;
    }

    100% {
        left: 0;
    }
}